Comparing h-BN and MgO tunnel barriers for scaled magnetic tunnel junctions

Magnetic tunnel junctions (MTJ) with MgO/Fe based interfaces and perpendicular spin directions form the basis of present-day spin-transfer torque magnetic random-access memories. Many semiconductor devices, such as CMOS transistors, have undergone fundamental changes in materials design as dimensional scaling has progressed. Here, we consider how future scaling of MTJs might affect materials choices, comparing different tunnel barriers, such as 2D h-BN materials with existing MgO tunnel barriers. The different interfacial sites of h-BN on Ni or Co are compared in terms of their physisorptive or chemisorptive bonding and how this affects their transmission magnetoresistance, ability to create perpendicular magnetic isotropy, and unusual factors such as the pillow effect. These effects are balanced by the beneficial chemical thermodynamics of the existing MgO barriers and MgO/Fe interfaces.

Automated summary

Magnetic tunnel junctions with MgO/Fe interfaces and perpendicular spin directions are widely used in spin-transfer torque magnetic random-access memories. The future scaling of MTJs may affect materials choices, including comparing 2D h-BN materials with existing MgO tunnel barriers. The effects of different h-BN interfacial sites on Ni or Co are compared in terms of their magnetoresistance, magnetic isotropy, and the pillow effect, balanced against the favorable chemical thermodynamics of the existing MgO barriers and MgO/Fe interfaces.